1. Field of the Invention.
The present invention relates to a compacting press that includes a picker system for removing a green compact from the press.
2. Description of the Prior Art.
It is known to produce metal parts by compacting metal powder and heating the compacted metal powder to sinter the metal particles to produce a finished metal product. In one type of commercially available compacting press, metal powder is typically delivered to a feed shoe, or shuttle assembly. The feed shoe is movable on the press table between a retracted position and an extended position. In the extended position, metal powder in the feed shoe drops into a die cavity. The feed shoe is then retracted and then upper and lower punches compact the metal powder in the die cavity to form a green compact. A core rod is also extended to form any inner diameter of the powder metal part. The green compact is then ejected from the die cavity.
The green compact must then be removed from the area of the die and punches. At this stage of manufacture, the green compacts are relatively fragile, and require careful or sensitive handling. One prior art system for picking up and removing fragile green compacts from a press is illustrated in FIG. 1. As there shown, the prior art press 10 includes a platen 12 with a space or cavity in the platen holding a die 14. The prior art press includes a feed shoe assembly, shown schematically at 16, and a picker assembly 18 aligned opposite the feed shoe assembly 16, with the die 14 between them. The upper and lower punches (not shown) are vertically aligned with the die 14.
The prior art picker assembly 18 includes a support frame 20. The support frame 20 has a front rail 22, a back rail 24 and spaced side rails 26, 28. The frame includes two rods 27, 29 fixed to the side rails 26, 28 and supporting the frame on the platen surface. The two rods 27, 29 are not fixed to the platen, and the frame is pivotable about a horizontal axis where the rods rest atop the platen 12, such as shown at 30 in FIG. 1. The ends of the front rail 22 are clamped to plates 32 above bellows 34 of bellow assemblies. The bellow assemblies are fixed to the platen through threaded connections to studs extending upward from the platen.
A commercially available guide rail component 36 is mounted on the support frame 20. The guide rail component is a "ULTRAN SLIDE" rodless cylinder supplied by Bimba Manufacturing Company of Monee, Illinois. This guide component has two spaced parallel guide rods 38, 39 with a tube 40 between the two guide rods 38, 39. The tube 40 is hollow and carries an interior piston. A slide 42 is mounted on the tube 40 and guide rods 38, 39, and is magnetically driven by movement of the piston in the tube 40. The hollow tube 40 is connected to a source of pressurized air to drive the piston back and forth within the tube. The slide 42 has bearings that travel along the guide rods 38, 39. A gripper assembly 44 depends from an extension plate 46 that is fixed to the bottom of the slide 42.
The gripper assembly 44 includes a spacer block 48 fixed to the extension plate 46. On opposite sides of the spacer block 48, the gripper assembly includes two commercially available pneumatic cylinders 50. Each pneumatic cylinder 50 is connected to move one gripper arm 52 toward and away from each other. Opposite the pneumatic cylinders 50, each gripper arm 52 has a gripper finger 54. The two gripper fingers 54 extend toward each other and are shaped for picking up and carrying one or more green compacts (not shown).
A vertical central longitudinal plane 56 intersects the center of the die 14, and is centered between the gripper fingers 54. A vertical central transverse plane 58 intersects the vertical central longitudinal plane 56. The vertical central longitudinal plane 56 intersects the feed shoe 16, the tube 40 and slide 42 of the guide rail component 36, the front and back rails 22, 24 as well as the punches (not shown).
In operation, the gripper assembly 44 is spaced away from the die 14 when the feed shoe 16 delivers raw material to the die and when the punches move to compact the raw material in the die 14. After a green compact has been ejected from the die 14, the tube 40 is pressurized to thereby move the slide 42 toward the front rail 22, thereby moving the gripper assembly 44 toward the ejected compact. At this point, the gripper arms and gripper fingers are spaced apart from each other. To pick up the green compact, the pneumatic cylinders 50 are actuated to move the gripper arms 52 toward each other and toward the vertical central longitudinal plane 56. After the gripper fingers 54 contact the green compact, the bellows 34 are inflated to pivot the frame 20 about axis 30, thereby lifting the gripper arms 52, gripper fingers 54 and green compact. The pressure in tube 40 is then changed to move the piston and slide away from the front rail 22 and toward the back rail 24. The bellows remain inflated while the gripper arms, gripper fingers and compact are retracted. Thus, the gripper assembly 44 and green compact are moved away from the die, and may be placed on a conveyor or other system or support at a location spaced from the press.
As can be appreciated from FIG. 1, the combination of the feed shoe 16 and picker assembly 18 substantially obstruct the view of and block access to the die 14, particularly taking the position of the upper punch into consideration. To fully view the die cavity, to change the die over, to clean the die, or to work on the other tooling such as the punch requires removal of the entire picker assembly. Removal and reinstallation of the picker assembly requires removing and reinstalling the support frame from the press platen, typically by unclamping the frame from the bellows assemblies. Removal and reinstallation of the picker assembly adds to the set up time, thereby reducing manufacturing efficiency.